I opened up the files in DraftSight first to check. Then I opened it in the e-drawings and I'm not able to measure too.

The reason I found out is that you've the drawing entities on layout sheet (test1_4) on which measure is not working in e-drawings. Now if I copy/move data from test1_4 to model tab in DraftSight (should be doable in ACAD too), save and then reopen in e-drawings, the measure works fine. I believe this is what your customer is facing.

Try this on your end by moving the data over to model tab and open in e-drawings viewer and check.